The massive international manhunt to find jeans police killer continues. Former -- is hostages say the man seen here in Foley's -- -- -- video is one of three British citizens at hostages nickname The Beatles. They -- jailers torturers and executioners for the Islamic militant group. In an exclusive interview with Katie Couric on Yahoo! News police siblings said the US could have done more. To -- their brother I related really really hope that. And so -- agent's death. Push with the ticket take another look at our our -- our approach arm arm. Policy to to terrorists and hostage. Negotiations. And in Washington. Dire warnings from top military officials Defense Secretary chuck Cagle said -- is is is well funded and sophisticated as any group the US has ever seen. And beyond just a terrorist group. There are an imminent threat to every interest we have whether it's Iraq or -- anywhere else. But US officials have been clear the US air strikes nearly 100 so far have not been a knockout blow. We should expect -- to regroup. And stage new offensive. And then there's the big question about Syria. The chairman of the Joint Chiefs of Staff said that at some point ice this is safe haven there must be dealt -- Can be defeated without addressing. That part of their organization which resides and Syrian answers no. General Dempsey did not seem enthusiastic about US airstrikes in Syria but he didn't rule them out either. Karen Travers ABC news Washington.

This transcript has been automatically generated and may not be 100% accurate.

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